Facile synthesis of MgCo₂O₄ nanowires as binder-free flexible anode materials for high-performance Li-ion batteries

MgCo₂O₄ nanowires are synthesized for the first time through two-step synthesis method, followed by annealing of the MgCo₂O₄ precursors. The microstructure and morphology of MgCo₂O₄ nanowires are examined by powder X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. MgCo₂O₄ nanowires give rise to a BET surface area of 45.1 m² g⁻¹ and the adsorption average pore size of 11.5 nm. When tested as an anode for lithium-ion batteries, the MgCo₂O₄ nanowires electrode exhibit exceptional properties in terms of specific capacity, cycling performance, and rate capacity compared with previously reported Co-based binary metal oxides. For instance, when the current densities increase from 5, 10, 15, and 20 A g⁻¹, the discharge capacities of the MgCo₂O₄ nanowires electrode are about 649, 348, 188, and 121 mAh g⁻¹, respectively. The enhanced electrochemical performance of the MgCo₂O₄ nanowires can be mainly attributed to the nanostructures which lead to decreased lithium-ion diffusion distances and increased active sites for Li insertion/extraction reactions.